1. Technical Field
The present invention relates to the field of scatterometry metrology, and more particularly, to measurements of single first order diffraction signals.
2. Discussion of Related Art
Angularly resolved scatterometry is being widely utilized for monitoring of overlay errors between stacked periodic structures (e.g., grating on grating targets).
U.S. Pat. No, 7,403,293, which is incorporated herein by reference in its entirety, discloses using a supercontinuum light source arranged to generate a measurement beam, an optical system arranged to direct the measurement beam onto the substrate and a sensor for detecting radiation reflected and/for diffracted by the structure.